/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    SwapValues.java
 *    Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.SingleIndex;
import weka.core.UnsupportedAttributeTypeException;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> Swaps two values of a nominal attribute.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -C &lt;col&gt;
 *  Sets the attribute index (default last).
 * </pre>
 * 
 * <pre>
 * -F &lt;value index&gt;
 *  Sets the first value's index (default first).
 * </pre>
 * 
 * <pre>
 * -S &lt;value index&gt;
 *  Sets the second value's index (default last).
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class SwapValues extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedInstancesHandler, WeightedAttributesHandler {

    /** for serialization */
    static final long serialVersionUID = 6155834679414275855L;

    /** The attribute's index setting. */
    private final SingleIndex m_AttIndex = new SingleIndex("last");

    /** The first value's index setting. */
    private final SingleIndex m_FirstIndex = new SingleIndex("first");

    /** The second value's index setting. */
    private final SingleIndex m_SecondIndex = new SingleIndex("last");

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {

        return "Swaps two values of a nominal attribute.";
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws UnsupportedAttributeTypeException if the selected attribute is not
     *                                           nominal or if it only has one
     *                                           value.
     * @throws Exception                         if the input format can't be set
     *                                           successfully
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);
        m_AttIndex.setUpper(instanceInfo.numAttributes() - 1);
        m_FirstIndex.setUpper(instanceInfo.attribute(m_AttIndex.getIndex()).numValues() - 1);
        m_SecondIndex.setUpper(instanceInfo.attribute(m_AttIndex.getIndex()).numValues() - 1);
        if (!instanceInfo.attribute(m_AttIndex.getIndex()).isNominal()) {
            throw new UnsupportedAttributeTypeException("Chosen attribute not nominal.");
        }
        if (instanceInfo.attribute(m_AttIndex.getIndex()).numValues() < 2) {
            throw new UnsupportedAttributeTypeException("Chosen attribute has less than " + "two values.");
        }
        setOutputFormat();
        return true;
    }

    /**
     * Input an instance for filtering. The instance is processed and made available
     * for output immediately.
     * 
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input structure has been defined.
     */
    @Override
    public boolean input(Instance instance) {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }
        Instance newInstance = (Instance) instance.copy();
        if (!newInstance.isMissing(m_AttIndex.getIndex())) {
            if ((int) newInstance.value(m_AttIndex.getIndex()) == m_SecondIndex.getIndex()) {
                newInstance.setValue(m_AttIndex.getIndex(), m_FirstIndex.getIndex());
            } else if ((int) newInstance.value(m_AttIndex.getIndex()) == m_FirstIndex.getIndex()) {
                newInstance.setValue(m_AttIndex.getIndex(), m_SecondIndex.getIndex());
            }
        }
        push(newInstance, false); // No need to copy
        return true;
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(3);

        newVector.addElement(new Option("\tSets the attribute index (default last).", "C", 1, "-C <col>"));

        newVector.addElement(new Option("\tSets the first value's index (default first).", "F", 1, "-F <value index>"));

        newVector.addElement(new Option("\tSets the second value's index (default last).", "S", 1, "-S <value index>"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -C &lt;col&gt;
     *  Sets the attribute index (default last).
     * </pre>
     * 
     * <pre>
     * -F &lt;value index&gt;
     *  Sets the first value's index (default first).
     * </pre>
     * 
     * <pre>
     * -S &lt;value index&gt;
     *  Sets the second value's index (default last).
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String attIndex = Utils.getOption('C', options);
        if (attIndex.length() != 0) {
            setAttributeIndex(attIndex);
        } else {
            setAttributeIndex("last");
        }

        String firstValIndex = Utils.getOption('F', options);
        if (firstValIndex.length() != 0) {
            setFirstValueIndex(firstValIndex);
        } else {
            setFirstValueIndex("first");
        }

        String secondValIndex = Utils.getOption('S', options);
        if (secondValIndex.length() != 0) {
            setSecondValueIndex(secondValIndex);
        } else {
            setSecondValueIndex("last");
        }

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        options.add("-C");
        options.add("" + (getAttributeIndex()));
        options.add("-F");
        options.add("" + (getFirstValueIndex()));
        options.add("-S");
        options.add("" + (getSecondValueIndex()));

        return options.toArray(new String[0]);
    }

    /**
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String attributeIndexTipText() {

        return "Sets which attribute to process. This " + "attribute must be nominal (\"first\" and \"last\" are valid values)";
    }

    /**
     * Get the index of the attribute used.
     * 
     * @return the index of the attribute
     */
    public String getAttributeIndex() {

        return m_AttIndex.getSingleIndex();
    }

    /**
     * Sets index of the attribute used.
     * 
     * @param attIndex the index of the attribute
     */
    public void setAttributeIndex(String attIndex) {

        m_AttIndex.setSingleIndex(attIndex);
    }

    /**
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String firstValueIndexTipText() {

        return "The index of the first value " + "(\"first\" and \"last\" are valid values).";
    }

    /**
     * Get the index of the first value used.
     * 
     * @return the index of the first value
     */
    public String getFirstValueIndex() {

        return m_FirstIndex.getSingleIndex();
    }

    /**
     * Sets index of the first value used.
     * 
     * @param firstIndex the index of the first value
     */
    public void setFirstValueIndex(String firstIndex) {

        m_FirstIndex.setSingleIndex(firstIndex);
    }

    /**
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String secondValueIndexTipText() {

        return "The index of the second value " + "(\"first\" and \"last\" are valid values).";
    }

    /**
     * Get the index of the second value used.
     * 
     * @return the index of the second value
     */
    public String getSecondValueIndex() {

        return m_SecondIndex.getSingleIndex();
    }

    /**
     * Sets index of the second value used.
     * 
     * @param secondIndex the index of the second value
     */
    public void setSecondValueIndex(String secondIndex) {

        m_SecondIndex.setSingleIndex(secondIndex);
    }

    /**
     * Set the output format. Swapss the desired nominal attribute values in the
     * header and calls setOutputFormat(Instances) appropriately.
     */
    private void setOutputFormat() {

        Instances newData;
        ArrayList<Attribute> newAtts;
        ArrayList<String> newVals;

        // Compute new attributes

        newAtts = new ArrayList<Attribute>(getInputFormat().numAttributes());
        for (int j = 0; j < getInputFormat().numAttributes(); j++) {
            Attribute att = getInputFormat().attribute(j);
            if (j != m_AttIndex.getIndex()) {
                newAtts.add((Attribute) att.copy());
            } else {

                // Compute list of attribute values

                newVals = new ArrayList<String>(att.numValues());
                for (int i = 0; i < att.numValues(); i++) {
                    if (i == m_FirstIndex.getIndex()) {
                        newVals.add(att.value(m_SecondIndex.getIndex()));
                    } else if (i == m_SecondIndex.getIndex()) {
                        newVals.add(att.value(m_FirstIndex.getIndex()));
                    } else {
                        newVals.add(att.value(i));
                    }
                }
                Attribute newAtt = new Attribute(att.name(), newVals);
                newAtt.setWeight(att.weight());
                newAtts.add(newAtt);
            }
        }

        // Construct new header

        newData = new Instances(getInputFormat().relationName(), newAtts, 0);
        newData.setClassIndex(getInputFormat().classIndex());
        setOutputFormat(newData);
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new SwapValues(), argv);
    }
}
